阅读说明：本技术 一种双层三元氧化物的光电突触器件及其制备和工作方法 (Photoelectric synapse device of double-layer ternary oxide and preparation and working methods thereof ) 是由 杨志强 顾鹏 陈柯辛 李春梅 王金勇 蒋向东 李伟 于 2021-08-20 设计创作，主要内容包括：本发明提供一种双层三元氧化物的光电突触器件及其制备和工作方法,器件从上至下具有透明顶电极、n型金属掺杂钛酸锶氧化物薄膜、p型铝酸铜氧化物薄膜、透明底电极的垂直四层结构；多个透明顶电极形成的阵列等距排布在器件上表面；n型金属掺杂钛酸锶氧化物薄膜和p型铝酸铜氧化物薄膜用于构建光电突触器件的功能层,透明导电薄膜作为顶电极、底电极和光窗；所述的光电突触器件不仅具有器件结构和制备工艺简单等特点,还具有响应时间短和响应电流大的优点,其宽光谱响应可以解决电激励电读取突触器件工作带宽受限的问题,有望在未来神经形态芯片以及先进智能视觉系统中获得应用。(The invention provides a photoelectric synapse device of double-layer ternary oxide and a preparation method and a working method thereof, wherein the device is provided with a vertical four-layer structure of a transparent top electrode, an n-type metal doped strontium titanate oxide film, a p-type copper aluminate oxide film and a transparent bottom electrode from top to bottom; the array formed by the plurality of transparent top electrodes is arranged on the upper surface of the device at equal intervals; the n-type metal doped strontium titanate oxide film and the p-type copper aluminate oxide film are used for constructing a functional layer of the photoelectric synapse device, and the transparent conductive film is used as a top electrode, a bottom electrode and an optical window; the photoelectric synapse device not only has the characteristics of simple device structure and preparation process, but also has the advantages of short response time and large response current, the wide-spectrum response of the photoelectric synapse device can solve the problem that the working bandwidth of the electric excitation electric reading synapse device is limited, and the photoelectric synapse device is expected to be applied to a future neuromorphic chip and an advanced intelligent vision system.)

1. A double-layer ternary oxide optoelectronic synapse device, comprising: the device is provided with a transparent top electrode (1), an n-type metal doped strontium titanate oxide film (2), a p-type copper aluminate oxide film (3) and a transparent bottom electrode (4) which are in a vertical four-layer structure from top to bottom; the n-type metal doped strontium titanate oxide film and the p-type copper aluminate oxide film are used for constructing a functional layer of the photoelectric synapse device; the transparent conductive film is used as a top electrode, a bottom electrode and an optical window, and an array formed by a plurality of transparent top electrodes is equidistantly distributed on the upper surface of the device; the action potential of the front end of the visual synapse is simulated by optical signals with different energies, and the photocurrent response of the device is used for simulating the back current of the visual synapse.

2. The device of claim 1, wherein: the excitation source of the photoelectric synapse device is an optical signal with the wavelength of 450 nm-1550 nm.

3. The device of claim 1, wherein: the response time of the photoelectric synapse device is 1 ms-10 ms.

4. The device of claim 1, wherein: the transparent top electrode and the transparent bottom electrode are transparent conductive films, and the materials are selected from Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO).

5. The device of claim 1, wherein: the transparent top electrode is obtained by performing radio frequency sputtering on an Indium Tin Oxide (ITO) target or an Indium Zinc Oxide (IZO) target, and the thickness of the film is 50 nm-100 nm.

6. The device of claim 1, wherein: the n-type metal doped strontium titanate oxide film is obtained by adopting a method of radio frequency co-sputtering of a strontium titanate ceramic target and metal particles, the thickness of the film is 20 nm-60 nm, and the metal particles are selected from one of copper (Cu), silver (Ag) and ruthenium (Ru); the p-type copper aluminate oxide film is obtained by a radio frequency sputtering method of a copper aluminate ceramic target, and the thickness of the film is 30 nm-80 nm.

7. A method of operating a double layer ternary oxide optoelectronic synapse device as claimed in any one of claims 1 to 6 wherein: when a photostimulation signal acts on the photoelectric synapse device, the photostimulation signal interacts with the n-type metal doped strontium oxide thin film and excites a photon-generated carrier, and the excited photon-generated carrier is separated by an electric field built in a PN junction of an interface of the n-type metal doped strontium oxide thin film (2) and the p-type copper aluminate oxide thin film (3), and then is captured by oxygen vacancies or/and defects introduced by nano metal particles; when the optical excitation signal is removed from the device, the defects introduced by the oxygen vacancies or/and the nano-metal particles release the captured photogenerated carriers, so that continuous photocurrent degradation is generated and the degradation degree of the degradation degree changes along with the changes of the wavelength, the intensity and the excitation time of the excitation light; when an optical signal is used as the action potential of a synapse device and a decaying continuous photocurrent is used as the postsynaptic current of the device, the double-layer ternary oxide photoelectric synapse device has a plurality of bionic visual synapse functions of synapse plasticity, empirical learning and color recognition in the wavelength range of 450 nm-1550 nm.

8. A method of fabricating a bilayer ternary oxide optoelectronic synapse device as claimed in any one of claims 1-6 comprising the steps of:

the method comprises the following steps: selecting transparent conductive glass Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO) as a substrate, and using a transparent conductive film on the upper surface of the substrate as a lower electrode of the photoelectric synapse device; cleaning and drying;

step two: dividing the transparent conductive glass into two areas, namely a light excitation signal input area and a post-synaptic current detection area, protecting the post-synaptic current detection area, and reserving a window in the light excitation signal input area; obtaining a p-type copper aluminate oxide film by adopting a radio frequency sputtering method;

step three: on the basis of the second step, obtaining the n-type metal doped strontium titanate oxide film by adopting a radio frequency co-sputtering method;

step four: and on the basis of the third step, adopting an Indium Tin Oxide (ITO) target or an Indium Zinc Oxide (IZO) target and combining a mask plate radio frequency sputtering method to obtain the equidistant transparent top electrodes arranged in an array.

Technical Field

The invention relates to a photoelectric synapse device of a double-layer ternary oxide and a preparation method and a working method thereof, belonging to the technical field of semiconductor optoelectronic devices.

Background

In the past hundred years, the artificial vision system has brought great convenience to our lives, and its application is becoming more and more widespread. The human exploration in unknown fields reaches unprecedented height, and in the process of exploring the outside, a traditional artificial vision system consisting of a photoelectric detector and a computer plays an important role. However, with the advent of artificial intelligence technology, big data and post-molar times, the traditional artificial vision system based on von neumann architecture and Si-CMOS process will face some problems such as energy consumption of data processing, solution of unstructured and real-time problems, and increase of computation speed. This is mainly due to the separation of the memory unit and the data processing unit in the von neumann architecture computer. The human visual system formed based on the neural network has the characteristics of integrating perception, operation and memory, and can process information with low energy consumption and high speed. Therefore, the processing mode for simulating human vision is to construct a new generation artificial vision system, and is one of the ways for breaking the bottleneck of von neumann. The basic unit of the visual neural network system is synapse, and the photoelectric device with synapse function is the basis for constructing a new generation of artificial visual system. In recent years, many researchers have prepared many optoelectronic synapse devices for artificial vision systems, wherein ternary oxide series are not available, but these optoelectronic synapse devices based on ternary oxide often do not realize wide-spectrum, fast-response synapse function, and are not favorable for detection and processing of infrared images applied to new generation vision systems.

Disclosure of Invention

The invention aims to provide a photoelectric synapse device of a double-layer ternary oxide, which can realize wide spectrum, fast response and multiple bionic visual synapse functions with synapse plasticity, experience learning and color recognition.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a photoelectric synapse device of double-layer ternary oxide is provided with a transparent top electrode 1, an n-type metal doped strontium titanate oxide film 2, a p-type copper aluminate oxide film 3 and a transparent bottom electrode 4 which are in a vertical four-layer structure from top to bottom; the n-type metal doped strontium titanate oxide film and the p-type copper aluminate oxide film are used for constructing a functional layer of the photoelectric synapse device; the transparent conductive film is used as a top electrode, a bottom electrode and an optical window, and an array formed by a plurality of transparent top electrodes is equidistantly distributed on the upper surface of the device; the action potential of the front end of the visual synapse is simulated by optical signals with different energies, and the photocurrent response of the device is used for simulating the back current of the visual synapse.

Preferably, the excitation source of the optoelectronic synapse device is an optical signal with a wavelength of 450nm to 1550 nm.

Preferably, the response time of the optoelectronic synapse device is between 1ms and 10 ms.

Preferably, the transparent top electrode and the transparent bottom electrode are transparent conductive films, and the material is selected from Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO).

Preferably, the transparent top electrode is obtained by performing radio frequency sputtering on an Indium Tin Oxide (ITO) target or an Indium Zinc Oxide (IZO) target, and the thickness of the film is 50 nm-100 nm.

As a preferred mode, the n-type metal doped strontium titanate oxide film is obtained by adopting a method of radio frequency co-sputtering a strontium titanate ceramic target and metal particles, the thickness of the film is 20 nm-60 nm, and the metal particles are selected from one of copper Cu, silver Ag and ruthenium Ru; the p-type copper aluminate oxide film is obtained by a radio frequency sputtering method of a copper aluminate ceramic target, and the thickness of the film is 30 nm-80 nm.

The invention also provides a working method of the photoelectric synapse device of the double-layer ternary oxide, which comprises the following steps: when a light excitation signal acts on the photoelectric synapse device, the light excitation signal interacts with the n-type metal doped strontium titanate oxide film and excites a photon-generated carrier, and the excited photon-generated carrier is separated by an electric field built in a PN junction of the interface of the n-type metal doped strontium titanate oxide film 2 and the p-type copper aluminate oxide film 3 and then is captured by oxygen vacancies or/and defects introduced by nano metal particles; when the optical excitation signal is removed from the device, the defects introduced by the oxygen vacancies or/and the nano-metal particles release the captured photogenerated carriers, so that continuous photocurrent degradation is generated and the degradation degree of the degradation degree changes along with the changes of the wavelength, the intensity and the excitation time of the excitation light; when an optical signal is used as the action potential of a synapse device and a decaying continuous photocurrent is used as the postsynaptic current of the device, the double-layer ternary oxide photoelectric synapse device has a plurality of bionic visual synapse functions of synapse plasticity, empirical learning and color recognition in the wavelength range of 450 nm-1550 nm.

The invention also provides a preparation method of the photoelectric synapse device of the double-layer ternary oxide, which comprises the following steps:

the method comprises the following steps: selecting transparent conductive glass Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO) as a substrate, and using a transparent conductive film on the upper surface of the substrate as a lower electrode of the photoelectric synapse device; and cleaning and drying.

Step two: dividing the transparent conductive glass into two areas, namely a light excitation signal input area and a post-synaptic current detection area, protecting the post-synaptic current detection area, and reserving a window in the light excitation signal input area; and obtaining the p-type copper aluminate oxide film by adopting a radio frequency sputtering method.

Step three: and on the basis of the second step, obtaining the n-type metal doped strontium titanate oxide film by adopting a radio frequency co-sputtering method.

Step four: and on the basis of the third step, adopting an Indium Tin Oxide (ITO) target or an Indium Zinc Oxide (IZO) target and combining a mask plate radio frequency sputtering method to obtain the equidistant transparent top electrodes arranged in an array.

The invention has the beneficial effects that: the optical signal is used as the action potential of a synapse device, the separation of photogenerated carriers and the capture and release of the photogenerated carriers by the built-in electric field of the PN junction at the interface of the n-type metal doped strontium titanate oxide film 2 and the p-type copper aluminate oxide film 3 and the defects introduced by oxygen vacancies or/and nano metal particles are ingeniously utilized, the continuous photocurrent decay is generated, and the multiple bionic visual synapse functions of synapse plasticity, empirical learning and color recognition are realized. The photoelectric synapse device not only has the characteristics of simple device structure and preparation process, but also has the advantages of short response time and large response current, the wide-spectrum response of the photoelectric synapse device can solve the problem that the working bandwidth of the electric excitation electric reading synapse device is limited, and the photoelectric synapse device is expected to be applied to a future neuromorphic chip and an advanced intelligent vision system.

Drawings

Fig. 1 is a schematic structural view of the present invention.

FIG. 2 shows a double-layered ternary oxide photoelectric synapse device comprising an n-type copper-doped strontium titanate oxide thin film and a p-type copper aluminate oxide thin film prepared in an example, with a pulse width of 2ms, a wavelength of 520nm, and an optical power density of 20mW/cm²Photocurrent response curve under the excitation of the optical signal.

Fig. 3(a), (b), (c), (d), (e) and (f) respectively show the photocurrent response curve and the continuous photocurrent decay phenomenon of a double-layer ternary oxide photoelectric synapse device composed of the n-type copper-doped strontium titanate oxide thin film and the p-type copper aluminate oxide thin film prepared in the example under the excitation of optical signals with wavelengths of 450nm, 520nm, 780nm, 980nm, 1330nm and 1550 nm.

1 is a transparent top electrode, 2 is an n-type metal doped strontium titanate oxide film, 3 is a p-type copper aluminate oxide film, 4-bit transparent bottom electrode, and 5 is a light excitation signal.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

A photoelectric synapse device of double-layer ternary oxide is provided with a transparent top electrode 1, an n-type metal doped strontium titanate oxide film 2, a p-type copper aluminate oxide film 3 and a transparent bottom electrode 4 which are in a vertical four-layer structure from top to bottom; the n-type metal doped strontium titanate oxide film and the p-type copper aluminate oxide film are used for constructing a functional layer of the photoelectric synapse device; the transparent conductive film is used as a top electrode, a bottom electrode and an optical window, and an array formed by a plurality of transparent top electrodes is equidistantly distributed on the upper surface of the device; the action potential of the front end of the visual synapse is simulated by optical signals with different energies, and the photocurrent response of the device is used for simulating the back current of the visual synapse.

The excitation source of the photoelectric synapse device is an optical signal with the wavelength of 450 nm-1550 nm.

The response time of the photoelectric synapse device is 1 ms-10 ms.

The transparent top electrode and the transparent bottom electrode are transparent conductive films, and the materials are selected from Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO).

The transparent top electrode is obtained by performing radio frequency sputtering on an Indium Tin Oxide (ITO) target or an Indium Zinc Oxide (IZO) target, and the thickness of the film is 50 nm-100 nm.

The n-type metal doped strontium titanate oxide film is obtained by adopting a method of radio frequency co-sputtering of a strontium titanate ceramic target and metal particles, the thickness of the film is 20 nm-60 nm, and the metal particles are selected from one of copper (Cu), silver (Ag) and ruthenium (Ru); the p-type copper aluminate oxide film is obtained by a radio frequency sputtering method of a copper aluminate ceramic target, and the thickness of the film is 30 nm-80 nm.

The embodiment also provides a working method of the photoelectric synapse device of the double-layer ternary oxide, which comprises the following steps: when a light excitation signal acts on the photoelectric synapse device, the light excitation signal interacts with the n-type metal doped strontium titanate oxide film and excites a photon-generated carrier, and the excited photon-generated carrier is separated by an electric field built in a PN junction of the interface of the n-type metal doped strontium titanate oxide film 2 and the p-type copper aluminate oxide film 3 and then is captured by oxygen vacancies or/and defects introduced by nano metal particles; when the optical excitation signal is removed from the device, the defects introduced by the oxygen vacancies or/and the nano-metal particles release the captured photogenerated carriers, so that continuous photocurrent degradation is generated and the degradation degree of the degradation degree changes along with the changes of the wavelength, the intensity and the excitation time of the excitation light; when an optical signal is used as the action potential of a synapse device and a decaying continuous photocurrent is used as the postsynaptic current of the device, the double-layer ternary oxide photoelectric synapse device has a plurality of bionic visual synapse functions of synapse plasticity, empirical learning and color recognition in the wavelength range of 450 nm-1550 nm.

The embodiment also provides a preparation method of the photoelectric synapse device of the double-layer ternary oxide, which comprises the following steps:

the method comprises the following steps: selecting transparent conductive glass Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO) as a substrate, and using a transparent conductive film on the upper surface of the substrate as a lower electrode of the photoelectric synapse device; and cleaning and drying.

Step two: dividing the transparent conductive glass into two areas, namely a light excitation signal input area and a post-synaptic current detection area, protecting the post-synaptic current detection area, and reserving a window in the light excitation signal input area; and obtaining the p-type copper aluminate oxide film by adopting a radio frequency sputtering method.

Step three: on the basis of the second step, the n-type metal doped strontium titanate oxide film is obtained by adopting a radio frequency co-sputtering method

Step four: and on the basis of the third step, adopting an Indium Tin Oxide (ITO) target or an Indium Zinc Oxide (IZO) target and combining a mask plate radio frequency sputtering method to obtain the equidistant transparent top electrodes arranged in an array.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.